Seamlessly embedded heart rate monitor

ABSTRACT

This is directed to an electronic device having an integrated sensor for detecting a user&#39;s cardiac activity and cardiac electrical signals. The electronic device can include a heart sensor having several leads for detecting a user&#39;s cardiac signals. The leads can be coupled to interior surfaces of the electronic device housing to hide the sensor from view, such that electrical signals generated by the user can be transmitted from the user&#39;s skin through the electronic device housing to the leads. In some embodiments, the leads can be coupled to pads placed on the exterior of the housing. The pads and housing can be finished to ensure that the pads are not visibly or haptically distinguishable on the device, thus improving the aesthetic qualities of the device. Using the detected signals, the electronic device can identify or authenticate the user and perform an operation based on the identity of the user. In some embodiments, the electronic device can determine the user&#39;s mood from the cardiac signals and provide data related to the user&#39;s mood.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.12/358,905, filed Jan. 23, 2009 (now U.S. Pat. No. 8,615,290), whichclaims priority to U.S. Provisional Patent Application No. 61/111,498,filed Nov. 5, 2008. Each of these earlier applications is incorporatedby reference herein in its entirety.

BACKGROUND OF THE INVENTION

This is directed to providing a seamless heart-rate monitor in anelectronic device.

Many electronic devices are used to store personal or confidentialinformation. In particular, portable electronic devices such as cellulartelephones, personal assistants, and music players are often used tostore or access e-mail, contact lists, communications history, remotelyaccessed accounts (e.g., telephone, banking or credit card accounts), orother information that a user may regard as personal or private. Inaddition, several users may use the same electronic device. For example,several users in a household may use the same computer or portable musicplayer. As another example, a user may lend an electronic device to afriend (e.g., lend an iPod, available from Apple Inc. to a friend for aworkout or a trip). To enhance each user's experience with theelectronic device, the electronic device can include several profilesthat can be loaded and provided to the users of the device. Each profilecan be associated with a particular user, and include several settingsthat allow the electronic device interface user interaction components,and available data or applications to be personalized for the user.

The electronic device can use several approaches to identify the user ofthe electronic device and provide access to the user's private andpersonal information, or to load the user's personal profile. In someembodiments, the electronic device can identify or authenticate a userbased on an input provided by the user, such as a password or keyprovided using an input mechanism. In some embodiments, the electronicdevice can include one or more sensors operative to detect afingerprint, voice print, facial features, or other biometriccharacteristics of a user.

Other biometric-based approaches can be used to authenticate a user. Insome embodiments, an electronic device can authenticate a user based onthe attributes of the user's heartbeat. For example, the durations ofparticular portions of a user's heart rhythm, or the relative size ofpeaks of a user's electrocardiogram (EKG) can be processed and comparedto a stored profile to authenticate a user of the device. To detect auser's heartbeat or heart rhythm, however, the electronic device mustprovide at least two leads that the user contacts to detect the user'scardiac signals. Although the leads can simply be placed on the exteriorsurface of the device housing, for example in a defined location wherethe user may place a finger, this approach is not aestheticallypleasing, and may cause some prospective buyers to consider otherdevices. In addition, such an approach may require the user to perform aspecific authentication action—viz., placing a finger on the one or moreleads, then unlocking or accessing the electronic device features (e.g.,by moving a slider across the screen). This additional step may in factbe so encumbering that users disable the authentication feature andinstead use an unsecured electronic device.

SUMMARY OF THE INVENTION

This is directed to an electronic device having a seamlessly integratedcardiac sensor. The cardiac sensor can be integrated in any suitableportion of the electronic device, including for example a portion withwhich the user is typically in contact (e.g., an input mechanism or ahousing held by the user), or metallic or conductive portions of thedevice.

The electronic device can include any suitable type of electronicdevice, including for example a portable electronic device that the usermay hold in hand (e.g., a portable media player or a cellulartelephone), a larger portable electronic device (e.g., a laptopcomputer), or a substantially fixed electronic device. The electronicdevice may include software or hardware operative to process the outputof a cardiac sensor to extract, from the received output,characteristics of the user's heartbeat, heart rate, or other cardiacsignals. For example, the electronic device may extract one or morecharacteristic durations associated with the user's heart rate. Asanother example, the electronic device may extract one or morecharacteristic amplitudes or amplitude ratios associated with the user'sheart rate.

Once the electronic device has identified one or more characteristics ofthe user's heart rate, heartbeat, or other cardiac signals, theelectronic device can compare the one or more identified characteristicswith cardiac signal characteristics of authorized users that have beenstored in memory. In response to determining that the identifiedcharacteristics correspond to those of an authorized user (e.g., matchthose stored in memory), the electronic device can provide the user withaccess to the electronic device and load the identified user's personalsettings and data.

To determine the user's heart rate, heartbeat, or other cardiac signals,the electronic device can include one or more sensors embedded in thedevice. The one or more sensors can include leads for receivingelectrical signals from the user's heart. For example, the one or moresensors can include leads associated with the user's left and rightsides, and lead associated with the ground. To provide an electricalsignal from the user to the processing circuitry, the leads can beexposed such that the user may directly contact the leads, or mayinstead or in addition be coupled to an electrically conductive portionof the device enclosure (e.g., a metallic bezel or housing forming theexterior of the device).

Because each electronic device can include several leads, the leads maybe electrically isolated to avoid shorting or interference among leads.In some embodiments, an electrically isolating component can be insertedbetween adjacent leads. Alternatively, if the electronic deviceenclosure is constructed from a material having insufficientconductivity for transmitting detected cardiac electrical signals, thedistance along the enclosure between adjacent leads can be sufficient toisolate the leads. In addition, to ensure that the aesthetic appeal andappearance of the electronic device is retained, one or more of theisolating components, the leads themselves, and the device enclosure canbe finished using a suitable process to disguise the leads.

In some embodiments, if the electrical conductivity of portions of theelectronic device enclosure and the leads are suitably selected anddesigned, the leads can be positioned underneath the exterior surface ofthe enclosure while providing sufficient conductivity for detectingcardiac electrical signals and avoiding shorting or interference betweenadjacent leads. For example, the sensor leads can be constructed from asilver based compound having high electrical conductivity, while theelectronic device enclosure can be constructed from steel and aluminum,both having lower electrical conductivity. By placing several leads atsubstantially larger distances apart along the electronic deviceenclosure than the thickness of the enclosure, electronic signals can betransmitted through the steel or aluminum enclosure to a silver basedlead underneath the enclosure, but not along the surface of theenclosure to cause adjacent leads to short.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present invention, its nature andvarious advantages will be more apparent upon consideration of thefollowing detailed description, taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a schematic view of an illustrative electronic device forreceiving the output of one or more sensors in accordance with oneembodiment of the invention;

FIG. 2 is a graphical representation of illustrative electrical activityof a heart during a heartbeat;

FIG. 3 is a schematic view of an illustrative electronic device havingseveral integrated leads in accordance with one embodiment of theinvention;

FIG. 4A is a cross-sectional view of an illustrative electronic devicehaving a bezel with an embedded heart sensor lead in accordance with oneembodiment of the invention;

FIG. 4B is a cross-sectional view of another illustrative electronicdevice having a bezel with an embedded heart sensor lead in accordancewith one embodiment of the invention;

FIG. 5 is a schematic view of an illustrative electronic device usingportions of the bezel as leads in accordance with one embodiment of theinvention; and

FIG. 6 is a flowchart of an illustrative process for performing anelectronic device operation based on a user's cardiac signal inaccordance with one embodiment of the invention.

DETAILED DESCRIPTION

FIG. 1 is a schematic view of an illustrative electronic device forreceiving the output of one or more sensors in accordance with oneembodiment of the invention. Electronic device 100 can include controlcircuitry 102, storage 104, memory 106, input/output circuitry 108,communications circuitry 110, and heart sensor 112. In some embodiments,one or more of electronic device components 100 can be combined oromitted (e.g., combine storage 104 and memory 106). In some embodiments,electronic device 100 can include other components not combined orincluded in those shown in FIG. 1 (e.g., motion detection components, apower supply such as a battery or kinetics, a display, bus, or inputmechanism), or several instances of the components shown in FIG. 1. Forthe sake of simplicity, only one of each of the components is shown inFIG. 1.

Control circuitry 102 can include any processing circuitry or processoroperative to control the operations and performance of electronic device100. For example, control circuitry 100 can be used to run operatingsystem applications, firmware applications, media playback applications,media editing applications, or any other application. In someembodiments, the control circuitry can drive a display and processinputs received from a user interface.

Storage 104 can include, for example, one or more storage mediumsincluding a hard-drive, solid state drive, flash memory, permanentmemory such as ROM, any other suitable type of storage component, or anycombination thereof. Storage 104 can store, for example, media data(e.g., music and video files), application data (e.g., for implementingfunctions on device 100), firmware, user preference information data(e.g., media playback preferences), authentication information (e.g.libraries of data associated with authorized users), lifestyleinformation data (e.g., food preferences), exercise information data(e.g., information obtained by exercise monitoring equipment),transaction information data (e.g., information such as credit cardinformation), wireless connection information data (e.g., informationthat can enable electronic device 100 to establish a wirelessconnection), subscription information data (e.g., information that keepstrack of podcasts or television shows or other media a user subscribesto), contact information data (e.g., telephone numbers and emailaddresses), calendar information data, and any other suitable data orany combination thereof.

Memory 106 can include cache memory, semi-permanent memory such as RAM,and/or one or more different types of memory used for temporarilystoring data. In some embodiments, memory 106 can also be used forstoring data used to operate electronic device applications, or anyother type of data that can be stored in storage 104. In someembodiments, memory 106 and storage 104 can be combined as a singlestorage medium.

Input/output circuitry 108 can be operative to convert (andencode/decode, if necessary) analog signals and other signals intodigital data. In some embodiments, input/output circuitry 108 can alsoconvert digital data into any other type of signal, and vice-versa. Forexample, input/output circuitry 108 can receive and convert physicalcontact inputs (e.g., from a multi-touch screen), physical movements(e.g., from a mouse or sensor), analog audio signals (e.g., from amicrophone), or any other input. The digital data can be provided to andreceived from processor 102, storage 104, memory 106, heart sensor 112,or any other component of electronic device 100. Although input/outputcircuitry 108 is illustrated in FIG. 1 as a single component ofelectronic device 100, several instances of input/output circuitry canbe included in electronic device 100.

Electronic device 100 can include any suitable mechanism or componentfor allowing a user to provide inputs to input/output circuitry 108. Forexample, electronic device 100 can include any suitable input mechanism,such as for example, a button, keypad, dial, a click wheel, or a touchscreen. In some embodiments, electronic device 100 can include acapacitive sensing mechanism, or a multi-touch capacitive sensingmechanism. Some sensing mechanisms are described in commonly owned U.S.Pat. Nos. 8,479,122 and 8,239,784, both of which are incorporated hereinin their entirety.

In some embodiments, electronic device 100 can include specializedoutput circuitry associated with output devices such as, for example,one or more audio outputs. The audio output can include one or morespeakers (e.g., mono or stereo speakers) built into electronic device100, or an audio component that is remotely coupled to electronic device100 (e.g., a headset, headphones or earbuds that can be coupled tocommunications device with a wire or wirelessly).

In some embodiments, I/O circuitry 108 can include display circuitry(e.g., a screen or projection system) for providing a display visible tothe user. For example, the display circuitry can include a screen (e.g.,an LCD screen) that is incorporated in electronics device 100. Asanother example, the display circuitry can include a movable display ora projecting system for providing a display of content on a surfaceremote from electronic device 100 (e.g., a video projector). In someembodiments, the display circuitry can include a coder/decoder (Codec)to convert digital media data into analog signals. For example, thedisplay circuitry (or other appropriate circuitry within electronicdevice 100) can include video Codecs, audio Codecs, or any othersuitable type of Codec.

The display circuitry also can include display driver circuitry,circuitry for driving display drivers, or both. The display circuitrycan be operative to display content (e.g., media playback information,application screens for applications implemented on the electronicdevice, information regarding ongoing communications operations,information regarding incoming communications requests, or deviceoperation screens) under the direction of control circuitry 102.Alternatively, the display circuitry can be operative to provideinstructions to a remote display (e.g., display 130, FIG. 1).

Communications circuitry 110 can include any suitable communicationscircuitry operative to connect to a communications network and totransmit communications (e.g., voice or data) from communications device100 to other devices within the communications network. Communicationscircuitry 110 can be operative to interface with the communicationsnetwork using any suitable communications protocol such as, for example,Wi-Fi (e.g., a 802.11 protocol), Bluetooth, radio frequency systems(e.g., 900 MHz, 1.4 GHz, and 5.6 GHz communication systems), infrared,GSM, GSM plus EDGE, CDMA, quadband, and other cellular protocols, VOIP,or any other suitable protocol.

In some embodiments, communications circuitry 110 can be operative tocreate a communications network using any suitable communicationsprotocol. For example, communications circuitry 110 can create ashort-range communications network using a short-range communicationsprotocol to connect to other devices. For example, communicationscircuitry 110 can be operative to create a local communications networkusing the Bluetooth® protocol to couple electronic device 100 with aBluetooth headset.

Electronic device 100 can include one more instances of communicationscircuitry 110 for simultaneously performing several communicationsoperations using different communications networks, although only one isshown in FIG. 1 to avoid overcomplicating the drawing. For example,electronic device 100 can include a first instance of communicationscircuitry 110 for communicating over a cellular network, and a secondinstance of communications circuitry 110 for communicating over Wi-Fi orusing Bluetooth®. In some embodiments, the same instance ofcommunications circuitry 110 can be operative to provide forcommunications over several communications networks.

In some embodiments, electronic device 100 can be coupled a host devicefor data transfers, synching the communications device, software orfirmware updates, providing performance information to a remote source(e.g., providing riding characteristics to a remove server) orperforming any other suitable operation that can require electronicdevice 100 to be coupled to a host device. Several electronic devices100 can be coupled to a single host device using the host device as aserver, and instead or in addition electronic device 100 can be coupledto several host devices (e.g., for each of the plurality of the hostdevices to serve as a backup for data stored in electronic device 100).

Heart sensor 112 can include any suitable sensor operative to detect auser's heartbeat, heart rate, or any other signal generated by theuser's heart. In some embodiments, heart sensor 112 can serve as an EKGmonitor. Heart sensor 112 can include one or more leads connected to theexterior of the electronic device such that the user may contact one ormore of the leads to provide an electrical signal associated with theuser's heart to heart sensor 112. The cardiac signals detected by theheart sensor leads can be coupled to a processor incorporated in heartsensor 112, or instead provided to processor 102. The processor may thenanalyze the received signals and generate, from the received signals,one or more characteristic quantities of the user's heartbeat or heartrate for authentication.

The heart sensor leads can be constructed from any suitable material. Insome embodiments, the heart sensor leads can be constructed from aspecific material selected for particular conductive properties thatpermit a more effective transmission of the electrical signalsreflecting the user's cardiac activity. For example, the heart sensorleads can be constructed from a silver based compound, which can providesuperior conductivity relative to other metallic compounds (e.g., steelor aluminum). In addition, the size and location of the leads can beselected to ensure that sufficient contact is made between the user(e.g., the user's hand or finger) and the leads for cardiac signals tobe detected. For example, each lead can include a pad or extended areaplaced on the outer or inner surface of an electronic device bezel orhousing. The pad or extended area can then be coupled to a wire or otherconnector for providing cardiac signals to a processor for processing.As another example, an entire portion of the electronic device enclosure(e.g., a portion of a bezel or housing) can serve as a lead for theheart sensor. In such embodiments, the portion of the enclosure can besufficiently electrically isolated from other conductive portions of theelectronic device housing to ensure that lead portions of the device donot short. In some embodiments, an accessory coupled to the electronicdevice can be used to detect a user's heart rate. For example, the leadscan be located in one or more earbuds or in a headset, for example as isdescribed in commonly assigned U.S. Publication No. 2008/0076972, whichis incorporated by reference herein in its entirety.

Using a heart sensor, the electronic device can detect and analyze theelectrical activity of the heart over time. FIG. 2 is a graphicalrepresentation of illustrative electrical activity of a heart during aheartbeat. Representation 200 may include a plot of the variation of theheart's electrical potential over time. A typical heartbeat may includeseveral variations of electrical potential, which may be classified intowaves and a complex. For example, representation 200 can include P wave202, QRS complex 210, and I wave 220. Some representations can inaddition include a U wave (not shown). The P wave can represent normalatrial depolarization, when the main electrical vector spreads from theright atrium to the left atrium. The shape and duration of the P wavecan be related to the size of the user's atrium (e.g., indicating atrialenlargement), and can be a first source of heartbeat characteristicsunique to a user.

The QRS complex can correspond to the depolarization of the heartventricles, and can be separated into three distinct waves—a Q wave, a Rwave and a S wave. Because the ventricles contain more muscle mass thanthe atria, the QRS complex is larger than the P wave. In addition, theHis/Purkinje system of the heart, which can increase the conductionvelocity to coordinate the depolarization of the ventricles, can causethe QRS complex to look “spiked” rather than rounded. The duration ofthe QRS complex of a healthy heart can be in the range of 60 to 100 ms,but can vary due to abnormalities of conduction. The duration of the QRScomplex can therefore serve as a second source of heartbeatcharacteristics unique to a user.

The duration, amplitude, and morphology of each of the Q, R and S wavescan vary in different individuals, and in particular can varysignificantly for users having cardiac diseases or cardiacirregularities. For example, a Q wave that is greater than ⅓ of theheight of the R wave, or greater than 40ms in duration can be indicativeof a myocardial infarction and provide a unique characteristic of theuser's heart. Similarly, other healthy ratios of Q and R waves can beused to distinguish different users' heartbeats.

Representation 200 may include one or more characteristic durations orintervals that can be used to distinguish different users. For example,representation 200 can include PR interval 204 and ST segment 212. PRinterval 204 can be measured from the beginning of P wave 202 to thebeginning of QRS complex 210. PR interval 204 can typically last 120 to200 ms. A PR interval 204 having a different duration can indicate oneor more defects in the heart, such as a first degree heart block (e.g.,PR interval 204 lasting more than 200 ms), a pre-excitation syndrome viaan accessory pathway that leads to early activation of the ventricles(e.g., PR interval 204 lasts less than 120 ms), or another type of heartblock (e.g., PR interval 204 is variable). ST segment 212 can bemeasured from QRS complex 210 to T wave 220, for example starting at thejunction between QRS complex 210 and ST segment 212 and ending at thebeginning of T wave 220. ST segment 212 can typically last from 80 to120 ms, and normally has a slight upward concavity. The combination ofthe length of ST segment 212, and the concavity or elevation of STsegment 212 can also be used to generate characteristic informationunique to each user's heartbeat.

T wave 220 can represent the repolarization or recovery of theventricles. The interval from the beginning of the QRS complex to theapex of the T wave can be referred to as the absolute refractory period.The last half of the T wave can be referred to as the relativerefractory period or vulnerable period. The amplitude of T wave 220, theduration of the absolute refractory period, and the relative refractoryperiod can also be used to define a characteristic of the user's heartrate.

QT interval 222, which can represent the total time needed for theventricles to depolarize and repolarize, can be measured from thebeginning of QRS complex 210 to the end of T wave 220. QT interval 222can typically last between 300 and 450 ms, and can vary based on thecondition of the user's heart rate. Several correction factors have beendeveloped to correct QT interval 222 for the heart rate. Both themeasured and corrected QT interval 222 values can be used to define aunique characteristic of a user's heartbeat.

Because a user's heartbeat or heart rate can vary slightly based on theuser's activity or mood, each authorized user can initially provide abase or standard heart rate, heartbeat, or electrical activity to thedevice prior to first use. For example, the electronic device can sampleseveral heartbeats or electrical activity at several different times todetect variations in the user's cardiac electrical activity. Theelectronic device can process detected signals to determine severalunique characteristics of the user's heart activity, and identify arange of suitable characteristic values for each of the processedcharacteristics. Based on the characteristic values and associatedranges, the electronic device can select one, all or a subset of thecharacteristics to define a unique heart activity profile for theauthorized user. The particular combination of characteristics andassociated ranges can be selected to minimize overlap with otherauthorized users, or based on characteristic values and ranges that donot fall within a range of average values and ranges (e.g., do not usecharacteristic values and ranges that an average user of the devicewould have).

The heart sensor of the electronic device can include several leads fordetecting the user's heart activity. The leads can be integrated in anysuitable portion of the electronic device. FIG. 3 is a schematic view ofan illustrative electronic device having several integrated leads inaccordance with one embodiment of the invention. Electronic device 300can include display 302 and bezel 310, and be portable such that a usercan hold electronic device with fingers extending against one of sides312 and 314 of bezel 310, and the user's thumb extending against theother of sides 312 and 314. Leads 322 and 324, which can includeconductive pads, can be coupled to sides 312 and 314 of bezel 310,respectively, such that when the user holds the device, the user's thumband fingers are placed in contact with leads 322 and 324. Alternatively,bezel 310 can include any other suitable number of leads, or any othersuitable distribution of leads along bezel 310 and in other portions ofelectronic device 300. The leads can detect the user's cardiac activitythrough the contact with the user's thumb and fingers, and provide thedetected activity to the electronic device processor for processing. Thesize of leads 322 and 324 can be selected based on any suitableconsideration, including for example the different possible positions ofa user's hands on the device, the amount of contact necessary to detectthe user's cardiac activity, preventing or reducing short circuits andother cardiac signal detection errors, manufacturing considerations(e.g., the minimum or maximum size leads that can be integrated in thebezel), aesthetic considerations (e.g., sizing leads 322 and 324 toreduce the visibility of leads 322 and 324), or any other suitableconsideration.

In some embodiments, electronic device 300 can include additional lead326 embedded in or behind display 302. Lead 326 can be operative todetect a user's heart activity as the user moves a finger across display302, for example in the vicinity of or directly over lead 326 (e.g., asthe user drags a finger over lead 326 to move a slider when unlockingthe electronic device). Using lead 326, the electronic device can detectan electrical signal from a different portion of the user's body (e.g.,leads 322 and 324 detect signals through a first hand, and lead 326detects signals through the second hand), which can provide theprocessor with additional information for determining characteristics ofthe user's cardiac activity.

Any suitable approach can be used to prevent leads 322, 324 and 326 fromshorting. 1n particular, electronic device 300 can include at least onenon-conductive component positioned between each of leads 322, 324 and326. For example, a rubber gasket can be positioned between leads 322and 324 (in bezel 310) and lead 326 (in display 302). In someembodiments, the cardiac electrical signals detected by leads 322, 324and 326 can be faint or have particular characteristics that requirematerials having particular properties (e.g., silver-based compounds) todetect and transmit. In such cases, although the material used for bezel310 or other electronic device components can be conductive, itsconductivity can be insufficient to transmit signals detected by lead322 directly to lead 324 (e.g., shorting leads 322 and 324). This mayallow leads 322 and 324 to be embedded directly in bezel 310 without theneed for additional isolating material, which can add cost andcomplexity to the manufacturing process.

To ensure that electronic device 300, and in particular bezel 310remains aesthetically pleasing, leads 322 and 324 can be finished toresemble bezel 310. For example, leads 322 and 324 can be polished orroughened to match the finish of bezel 310. As another example, aconductive coating can be applied to leads 322 and 324 to match thecolor, tone and reflectivity of bezel 310. In some embodiments, thetexture or feel of leads 322 and 324 can also be selected to renderleads 322 and 324 visibly and haptically indistinguishable or nearlyindistinguishable from bezel 310.

Leads 322 and 324 can be integrated in bezel 310 using any suitableapproach. In some embodiments, leads 322 and 324 can be positioned onthe exterior surface of bezel 310 and include an electrically conductivepath to the electronic device processor. FIG. 4A is a cross-sectionalview of an illustrative electronic device having a bezel with anembedded heart sensor lead in accordance with one embodiment of theinvention. Electronic device 400 can include display 402 and bezel 410.Lead 422 can be embedded along the outer surface of bezel 410 such thatlead 422 is exposed to the user during use. Connector 424 can be coupledto the inner surface of lead 422 and extend into electronic device 400to be coupled with a processor. In some embodiments, electronic device400 can in addition include an isolating layer positioned between lead422 and bezel 410 (not shown). The isolating layer can be constructedfrom any suitable material having non-conductive properties, includingfor example a ceramic material, plastic, rubber, or any other suitablematerial. Alternatively, if the material of bezel 410 is not conductive,or insufficiently conductive to cause several distinct leads 422positioned on bezel 410 from shorting, no isolating layer may benecessary.

FIG. 4B is a cross-sectional view of another illustrative electronicdevice having a bezel with an embedded heart sensor lead in accordancewith one embodiment of the invention. Electronic device 450 can includedisplay 452 and bezel 460. If the electrical conductivity and size ofbezel 460, and the strength or characteristics of the cardiac signalprovided by the user and detected by the heart sensor are adapted suchthat the signal can be transmitted along short distances in bezel 460,lead 472 of the heart sensor can be positioned against the back surfaceof bezel 460. Alternatively, lead 472 can be placed within the thicknessof bezel 460 (e.g., in a pocket within the bezel wall), but underneaththe outer surface of the bezel. The short thickness of bezel 460 canallow electrical signals to propagate from the user to the outer surfaceof bezel 460, through bezel 460, and into lead 472, which may in turntransmit the signals to a processor using connector 474. In addition, ifseveral leads are placed along different portions of bezel 460, thedistance between adjacent leads can be sufficiently large (e.g.,substantially larger than the thickness of bezel 460) that differentleads of bezel 460 cannot detect the same electrical signal.

In some embodiments, entire portions of the bezel can be used as leadsfor the heart sensor. FIG. 5 is a schematic view of an illustrativeelectronic device using portions of the bezel as leads in accordancewith one embodiment of the invention. Similar to electronic device 300(FIG. 3), electronic device 500 can include display 502 and bezel 510.Bezel 510 can be separated into several electrically isolated segments,for example segments 522 and 524. The segments can be electricallyisolated using isolating portions 530 and 532, which can be constructedfrom any suitable non-conductive material, such as for example acomposite material, a plastic, rubber, or any other suitable material.Although FIG. 5 shows bezel 510 broken into two segments having similarsizes, it will be understood that bezel 510 can be separated into anysuitable number of electrically isolated segments, and each segment canhave any suitable size. In particular, the sizes and distribution ofeach segment can be selected based on physiological considerations(e.g., where a user's hand will be positioned on the device, or aligningthe segments to contact particular portions of the user's body).

To ensure that electronic device 500 remains aesthetically pleasing,isolating portions 530 and 532 can be finished to resemble bezel 510.For example, isolating portions 530 and 532 can be polished or machinedto create a reflective surface matching the reflection of bezel 510. Asanother example, a reflective or finishing coating can be applied to thesurfaces of isolating portions 530 and 532 to match the finish of bezel510. In some embodiments, the texture of isolating portions 530 and 532can also be selected to render segments 522 and 524 visually andhaptically indistinguishable or nearly indistinguishable from isolatingportions 530 and 532.

Other heart sensor leads can be placed at any other suitable position onthe electronic device enclosure. For example, if the enclosure isconstructed from a bezel supporting a display and a housing forming theexterior surface of the device behind the display, one or more leads canbe embedded in or adjacent to the housing. For example, if the housingincludes a conductive section (e.g., a plastic housing with a metalliclogo in the center of the housing), the lead can be coupled to orintegrated in the conductive section.

The heart sensor and processor can detect and process the user's cardiacactivity at any suitable time. For example, the processor can receiveand process heart activity when the device is locked and held while inits locked state. As another example, the processor can receive andprocess heart activity as the user places a finger over lead 326 (e.g.,when the user slides a finger across the display to unlock the device)or when an input mechanism detects a particular input. As still anotherexample, the electronic device can receive and process heart activitydata in response to a user instruction or request to access a particularapplication or data that for which access is restricted. Upon receivingthe cardiac activity, the electronic device can extract one or morecharacteristics of the received activity and compare the extractedcharacteristics with the characteristics previously stored in memorythat were associated with authorized users. If the extractedcharacteristics match those of an authorized user, the electronic devicecan authenticate the identified user.

The electronic device can perform any suitable operation in response toidentifying and authenticating a user based on detected cardiac signals.In some embodiments, the electronic device can provide access torestricted applications, for example applications for which onlyparticular users have licenses or that only particular users havepurchased. In some embodiments, the electronic device can provide accessto particular data or application settings associated with an authorizeduser. For example, the electronic device can provide access to theidentified user's contact list, or to the identified user's e-mailaccount or telephone history. As another example, the electronic devicecan allow the user to access private banking applications, or conductfinancial transactions (e.g., transferring funds to different accounts,or purchasing merchandise) using the electronic device. In someembodiments, the electronic device can load user settings and profilesfor providing a customized display to the user. For example, theelectronic device can display icons or options in the manner set by theuser, or provide displays using a color scheme, fonts, or othercustomizable display attribute that are associated with the identifieduser.

In some embodiments, the electronic device can use the detected heartrate or heartbeat characteristics to determine the user's mood. Inparticular, because the allowable determined characteristics associatedwith each user can include a range of values, the electronic device candetermine the distribution of the detected characteristics in theallowable characteristic ranges. Using the determined distribution, theelectronic device can establish a user's mood and provide electronicdevice operations or data (e.g., media) associated with the extrapolatedmood. Systems and methods for providing mood-based electronic deviceoperations are discussed in more detail in commonly assigned U.S.Publication No. 2010/0011388, which is incorporated by reference hereinin its entirety.

In some embodiments, the electronic device can provide media playbackbased on the user's detected cardiac signal. For example, the electronicdevice can identify media having beats per minute or othercharacteristics that are associated with or related to the user'scardiac signal or heart rate, and play back the identified media. Asanother example, the media provided can have beats per minute faster orslower than the user's current heart rate to direct the user to workharder (e.g., during a workout) or to cool or calm the user down (e.g.,at the end of a workout).

FIG. 6 is a flowchart of an illustrative process for performing anelectronic device operation based on a user's cardiac signal inaccordance with one embodiment of the invention. Process 600 can beginat step 602. At step 604, the electronic device can detect a user'scardiac signal. For example, the electronic device can detect a user'sheart rate or heart beat using one or more leads connected to or placedon a housing, bezel, or other exterior surface of the electronic device.The electronic device can process the received signal using any suitableapproach, including for example to determine unique characteristics ofthe signal. Such characteristics can include, for example, durationsbetween peaks in an EKG signal, peak values or rations between peaks inthe EKG signal, or any other suitable characteristic. At step 606, theelectronic device can determine whether the user detected at step 604 isan authorized user. For example, the electronic device can compare thedetermined characteristics of the detected cardiac signals with alibrary of signals associate with known authorized users. If theelectronic device determines that the user is not authorized (e.g., thecharacteristics of the detected cardiac signal do not matchcharacteristics of a cardiac signal stored in memory), process 600 canmove to step 608.

At step 608, the electronic device can prevent access to restrictedelectronic device operations. For example, the electronic device canprevent the user from accessing personal or private informationassociated with other users. As another example, the electronic devicecan prevent the user from accessing applications or operationsassociated with particular users (e.g., applications purchased byparticular users). As still another example, the electronic device canprevent the user from accessing any electronic device operation (e.g.,no operation except for emergency calls). Process 600 can then end atstep 610.

If, at step 606, the electronic device instead determines that the useris authorized, process 600 can move to step 612. At step 612, theelectronic device can determine the restricted operations that areassociated with the user. For example, the electronic device candetermine the particular private data associated with the authorizeduser (e.g., e-mail accounts, contact lists and banking information). Asanother example, the electronic device can determine the particularoperations or applications associated with the authorized user (e.g.,applications purchased by the user using an applications store, orsystem controlling operations associated with an administrativeaccount). At step 614, the electronic device can provide access to theuser's determined restricted operations. For example, the electronicdevice can load determined data. As another example, the electronicdevice can provide links for launching determined personal or privateapplications. Process 600 can then end at step 610.

The above-described embodiments of the present invention are presentedfor purposes of illustration and not of limitation, and the presentinvention is limited only by the claims which follow.

1-23. (canceled)
 24. An electronic device comprising: a bezel, whereinan outer surface of at least a portion of the bezel comprises a firstvisual characteristic; and a heart sensor coupled to the at least aportion of the bezel and operative to detect a user's cardiac signal,wherein an outer surface of the heart sensor comprises a second visualcharacteristic that matches the first visual characteristic.
 25. Theelectronic device of claim 24, wherein each of the outer surface of theat least a portion of the bezel and the outer surface of the heartsensor comprises a portion of an outer surface of the electronic device.26. The electronic device of claim 24, wherein: the outer surface of theat least a portion of the bezel comprises a first finish; and the outersurface of the heart sensor comprises a second finish that matches thefirst finish.
 27. The electronic device of claim 24, wherein the outersurface of the heart sensor comprises a conductive coating that providesthe second visual characteristic.
 28. The electronic device of claim 24,wherein each of the first visual characteristic and the second visualcharacteristic comprises at least one of: a particular color; aparticular tone; and a particular reflectivity.
 29. An electronic devicefor detecting a user's cardiac signal, comprising: an enclosure; a heartsensor configured to detect the user's cardiac signal, the heart sensorcomprising: a first lead embedded in a first portion of the enclosure,wherein the first lead is configured to detect a first electrical signalof the user's cardiac signal via the user's contact with at least one ofthe first lead and the first portion of the enclosure; and a second leadembedded in a second portion of the enclosure, wherein the second leadis configured to detect a second electrical signal of the user's cardiacsignal via the user's contact with at least one of the second lead andthe second portion of the enclosure; and a processor coupled to theheart sensor and configured to receive and process the detected cardiacsignal.
 30. The electronic device of claim 29, wherein the first portionand the second portion are located on opposite sides of the electronicdevice.
 31. The electronic device of claim 29, wherein the first portionis electrically isolated from the second portion.
 32. The electronicdevice of claim 29, wherein: the first portion is separated from thesecond portion by a third portion of the enclosure; at least the thirdportion is constructed from a material having a first conductivity; andthe first conductivity is insufficient to transmit the first electricalsignal from the first lead to the second lead via the third portion. 33.The electronic device of claim 32, wherein: the material having thefirst conductivity comprises one of aluminum and steel; and the secondlead is constructed from a silver based compound.
 34. The electronicdevice of claim 32, wherein: the second lead is configured to detect thesecond electrical signal of the user's cardiac signal via the user'scontact with an exterior surface of the second portion; the second leadis positioned from the exterior surface of the second portion by athickness of the second portion; at least the thickness of the secondportion is constructed from a material having a second conductivity; andthe second conductivity is defined such that the second electricalsignal is not transmitted over a distance larger than the thickness ofthe second portion.
 35. The electronic device of claim 34, wherein thefirst lead and the second lead are positioned apart from one another ata distance larger than the thickness of the second portion.
 36. Theelectronic device of claim 29, wherein: the enclosure further comprisesat least one pocket underneath an outer surface of the enclosure; and atleast one of the first lead and the second lead is placed within the atleast one pocket.
 37. The electronic device of claim 29, wherein: anexterior surface of the enclosure comprises an exterior surface of thefirst portion; and the first lead is positioned underneath the exteriorsurface of the first portion.
 38. The electronic device of claim 37,wherein the first lead is configured to detect the first electricalsignal via the user's contact with the exterior surface of the firstportion.
 39. The electronic device of claim 29, further comprising: adisplay, wherein the enclosure supports the display, and wherein theenclosure forms an exterior surface of the electronic device behind thedisplay; and a third lead embedded with the display, wherein the thirdlead is configured to detect a third electrical signal of the user'scardiac signal via the user's contact with at least one of the thirdlead and the display.
 40. An electronic device for detecting a user'scardiac signal, comprising: a heart sensor configured to detect theuser's cardiac signal, the heart sensor comprising: a first leadembedded in a first portion of the electronic device, wherein the firstlead is configured to detect a first electrical signal of the user'scardiac signal via the user's contact with at least one of the firstlead and the first portion of the electronic device; and a second leadembedded in a second portion of the electronic device, wherein thesecond lead is configured to detect a second electrical signal of theuser's cardiac signal via the user's contact with at least one of thesecond lead and the second portion of the electronic device; and aprocessor coupled to the heart sensor and configured to process thefirst and second electrical signals of the user's cardiac signal. 41.The electronic device of claim 40, wherein: the first portion of theelectronic device comprises an enclosure of the electronic device; andthe second portion of the electronic device comprises a display screenexposed to the user through an opening in the enclosure of theelectronic device.
 42. The electronic device of claim 41, wherein: thefirst portion of the electronic device comprises a bezel of theenclosure; the electronic device further comprises a non-conductivecomponent positioned between the bezel and the display screen forelectrically isolating the first portion of the electronic device fromthe second portion of the electronic device.
 43. The electronic deviceof claim 40, wherein: the first portion of the electronic devicecomprises a first portion of an enclosure of the electronic device; andthe second portion of the electronic device comprises a second portionof the enclosure of the electronic device.